Search Externalities in Firm-to-Firm Trade

I develop a model of firm-to-firm search and matching to show that the impact of falling trade costs on firm sourcing decisions and consumer welfare depends on the relative size of search externalities in domestic and international markets. These externalities can be positive if firms share information about potential matches, or negative if the market is congested. Using unique firm-to-firm transaction-level data from Uganda, I show empirical evidence consistent with positive externalities in international markets and negative externalities in domestic markets. I then build a dynamic quantitative version for the model and show that, in Uganda, a 25% reduction in trade costs led to a 5.2% increase in consumer welfare, 15% of which was due to search externalities

Change in physical self-perceptions across the transition to secondary school: relationships with perceived teacher-emphasised achievement goals in physical education

Objectives: This study aimed to examine the effects of change in perceived teacher achievement goal emphasis in physical education (PE) on physical self-perceptions and self-esteem across the transition to secondary school. Design & Methods: A longitudinal design was adopted with three time points, one at the end of primary school and two during the first year of secondary school. Participants (N = 491) were cross-classified by primary (N = 42) and secondary (N = 46) PE class in order to examine the association between perceived class-level teacher-emphasised goals and within-class student goals with self-beliefs. Results: Personal approach goals and class perceptions of teacher mastery approach goal promotion were all positively associated with ratings of co-ordination, sport competence, flexibility, and endurance in primary school. More favourable perceptions of coordination, sport competence, strength, flexibility, and endurance during the first year of secondary school were predicted by an increase in performance approach goal emphasis, whereas ratings of sport competence and flexibility were negatively associated with an increase in mastery approach goal emphasis. Conclusions: Although not entirely consonant with theoretical predictions, current findings suggest that teacher-emphasised performance approach goals in PE can promote development of several physical self-perceptions in the initial year of secondary school

Antecedents of perceived coach autonomy supportive and controlling behaviors: coach psychological need satisfaction and well-being

Within the self-determination theory (Deci & Ryan, 2000) framework, research has considered the consequences of coaches’ autonomy supportive and controlling behaviors on various athlete outcomes (e.g., motivation and performance). The antecedents of such behaviors, however, have received little attention. Coaches (N = 443) from a variety of sports and competitive levels completed a self-report questionnaire to assess their psychological need satisfaction, well-being and perceived interpersonal behaviors toward their athletes. Structural equation modeling demonstrated that coaches’ competence and autonomy need satisfaction positively predicted their levels of psychological well-being, as indexed by positive affect and subjective vitality. In turn, coaches’ psychological well-being positively predicted their perceived autonomy support toward their athletes, and negatively predicted their perceived controlling behaviors. Overall, the results highlight the importance of coaching contexts that facilitate coaches’ psychological need satisfaction and well-being, thereby increasing the likelihood of adaptive coach interpersonal behavior toward athletes

Indirect Detection of Little Higgs Dark Matter

Little Higgs models with T parity contain an attractive dark matter candidate, the heavy photon. We compute the cross section of the heavy photon annihilation into Z-photon pairs, which turns out to be substantially higher than the previously computed cross section for the two photon final state. Unfortunately, even with this enhancement, the monochromatic photon flux from galactic heavy photon annihilation is unlikely to be detectable by GLAST or the currently operating atmospheric Cerenkov telescopes. We also compute the flux of high-energy neutrinos from the annihilation of the heavy photons captured by the Sun and the Earth. The maximum flux of upward-going muons due to such neutrinos is about 1 yr^{-1}km^{-2}.Comment: 13 pages, 3 figure

A Skills-Focused Approach to Improving Therapist Goniometry Accuracy Using a Simulation Laboratory

Goniometric measurements are widely used in the field of occupational therapy to measure range of motion, define and describe movement, and predict the functional implications of joint limitations. These measurements are further used in documentation and as a means of justifying reimbursement. While goniometrics are a hallmark of our practice, therapist competency is rarely assessed. This study sought to evaluate whether a skill focused, simulation assisted training could lead to improvements in accuracy and consistency of goniometric measurements. Ten therapists at a single facility completed goniometric testing utilizing a simulation module to assess three joint motions (shoulder abduction, elbow flexion and neck extension). Testing was followed by extended, joint specific education prior to retesting. Estimates of consistency improved for all joint motions from pre to post training. Measurement accuracy improved in shoulder abduction and neck extension. Therapists reported improved level of comfort for specific joint measurements and for goniometry in general. Training laboratories such as the one described in this paper, can be an effective way of establishing a consistent departmental standard, assessing current competency, and providing hands-on training in a new and innovative way

The exchange bias phenomenon in uncompensated interfaces: Theory and Monte Carlo simulations

We performed Monte Carlo simulations in a bilayer system composed by two thin films, one ferromagnetic (FM) and the other antiferromagnetic (AFM). Two lattice structures for the films were considered: simple cubic (sc) and a body center cubic (bcc). In both lattices structures we imposed an uncompensated interfacial spin structure, in particular we emulated a FeF2-FM system in the case of the (bcc) lattice. Our analysis focused on the incidence of the interfacial strength interactions between the films J_eb and the effect of thermal fluctuations on the bias field H_EB. We first performed Monte Carlo simulations on a microscopic model based on classical Heisenberg spin variables. To analyze the simulation results we also introduced a simplified model that assumes coherent rotation of spins located on the same layer parallel to the interface. We found that, depending on the AFM film anisotropy to exchange ratio, the bias field is either controlled by the intrinsic pinning of a domain wall parallel to the interface or by the stability of the first AFM layer (quasi domain wall) near the interface.Comment: 18 pages, 11 figure

Antecedents of perceived coach interpersonal behaviors: the coaching environment and coach psychological well- and ill-being

Embedded in the self-determination theory (Deci & Ryan, 2000) framework, we obtained self-report data from 418 paid and voluntary coaches from a variety of sports and competitive levels with the aim of exploring potential antecedents of coaches’ perceived autonomy supportive and controlling behaviors. Controlling for socially desirable responses, structural equation modeling revealed that greater job security and opportunities for professional development, and lower work–life conflict were associated with psychological need satisfaction, which, in turn, was related to an adaptive process of psychological well-being and perceived autonomy support toward athletes. In contrast, higher work–life conflict and fewer opportunities for development were associated with a distinct maladaptive process of thwarted psychological needs, psychological ill-being, and perceived controlling interpersonal behavior. The results highlight how the coaching context may impact upon coaches’ psychological health and their interpersonal behavior toward athletes. Moreover, evidence is provided for the independence of adaptive and maladaptive processes within the self-determination theory paradigm